1. Field of the Invention
This invention relates to an aqueous dispersion of at least one polymeric composition. The polymeric compositions used herein provide a relatively low solution viscosity when used in aqueous dispersions. The invention also relates to the preparation of such aqueous dispersions. The aqueous dispersions of this invention are particularly useful for use as or in overprint varnishes, inks, pigment dispersions, adhesives, coatings, and the like. The invention also relates to the use of the aqueous dispersions as support resins and to the emulsion polymers prepared therewith.
2. Related Background Art
Water based polymeric compositions are well known. For example, U.S. Pat. No. 5,521,267 describes water soluble and water insoluble polymer resins that are free of low molecular weight emulsifiers and which may be used as binders in water-borne paints.
Block copolymers having an A(BA).sub.n structure are a well known polymeric composition. For example, U.S. Pat. No. 5,362,819 describes an ABA curable block copolymer with an A block that is an unsaturated polyester, preferably having a mono-, or less desirably a di-, hydroxyl, carboxylic or amine end group, and a B block that is a flexible polymer having a glass transition temperature (Tg) of 0.degree. C. or less. The flexible polymers are said to include those prepared from conjugated diene monomers, as well as polyethers or saturated polyester, which are linked to the A block by an ester, amide, urea or urethane group.
U.S. Pat. No. 4,347,339 describes a water soluble cationic block copolymer having a first polymer block having amino functional groups, a majority of which are quaternary amino groups, and a second polymer block having amino functional groups, a majority of which are not quaternary amino groups. The polymer blocks may be linked with bridges of other polymers, but are preferably linked by including a functional group such as a chloride or epoxide in the first polymer block that reacts with the amino functional groups of the second polymer block.
U.S. Pat. No. 4,851,474 describes a block copolymer comprising at least one polyester block and an elastomeric polymer block such as a polymer of one or more conjugated dienes. The elastomeric block is functionalized to incorporate only terminal functional groups, i.e., no more than 2 functional groups per polymeric block.
U.S. Pat. No. 5,008,334 describes resins containing an ABA block copolymer having an A block which is a reaction product of a diol and one or more diepoxides and a B block of an epoxy-capped, carboxyl-terminated polybutadiene or polybutadiene/acrylonitrile copolymer. Amine resins which are prepared from a resin that is a mixture of (i) the reaction product of a diol and at least one diepoxide and (ii) the ABA block copolymer are used in electrocoating formulations.
U.S. Pat. No. 5,314,954 describes aromatic polyester-polystyrene block copolymers produced by the polycondensation of styrene polymers having terminal functional groups, e.g. hydroxy, amino or carboxyl groups, with an excess of aromatic dicarboxylic acid dihalides and then subjecting the resulting condensation product to interfacial polymerization with aromatic dihydroxy compounds. These aromatic polyester-polystyrene block copolymers are said to have a minimum of uncopolymerized styrene and to be useful for the preparation of optical instruments.
Polyester block copolymers that provide an elastic yarn having a high elastic recovery and a high heat resistance are disclosed by U.S. Pat. No. 5,384,184. The polyester block copolymer comprises (A) 30 to 90% by weight of polyester segments comprising a benzenedicarboxylic acid as the main acid component and a diol having 5 to 12 carbon atoms between the hydroxyl groups as the main glycol component and (B) 70 to 10% by weight of polyester segments comprising an aromatic dicarboxylic acid as the main acid component and ethylene glycol, trimethylene glycol, tetramethylene glycol or 1,4-cyclohexane dimethanol as the main glycol component.
U.S. Pat. No. 5,496,876 describes a polyetheramide block copolymer constituted by the copolycondensation of polyamide polymers having reactive end groups with polyether sequences having reactive end groups. These polyetheramide block copolymers are blended with a styrene/diene copolymer to form thermoplastic polymeric compositions.
U.S. Pat. No. 4,180,528 describes an ABA type block copolymer having an A block that is an addition polymer and a B block that is a linear saturated polyester. The A block and B block are joined by addition polymerization.
European Patent Application Publication No. 0687690/A describes a high temperature polymerization process to produce terminally unsaturated oligomers having relatively low molecular weights. It is further disclosed that the terminally unsaturated oligomers having a carboxylic acid group can be reacted with polyfunctional alcohols having two or more alcohol functionalities to form polyesters. There is, however, no disclosure of terminally unsaturated oligomers having relatively high functionality.
Water dispersions of polymeric compositions that are highly functional, preferably having high acid functionality, as well as a high molecular weight, but which do not readily gel would be highly desirable.